Display panel or portion thereof with a transitional graphical user interface



FIG. 1 is a front view of a display panel or portion thereof with a transitional graphical user interface showing a first image in a sequence of our design;

FIG. 2 is a front view of a display panel or portion thereof with a transitional graphical user interface showing a second image in the sequence thereof;

FIG. 3 is a front view of a display panel or portion thereof with a transitional graphical user interface showing a third image in the sequence thereof;

FIG. 4 is a front view of a display panel or portion thereof with a transitional graphical user interface showing a fourth image in the sequence thereof;

FIG. 5 is a front view of a display panel or portion thereof with a transitional graphical user interface showing a fifth image in the sequence thereof; and,

FIG. 6 is a front view of a display panel or portion thereof with a transitional graphical user interface showing a sixth image in the sequence thereof.

The appearance of the image sequentially transitions between the images shown in FIGS. 1 through 6. The process or period in which one image transitions into another forms no part of the claimed design.

The outermost broken line rectangle illustrates a display panel or portion thereof that forms no part of the claimed design. 

CLAIM The ornamental design for a display panel or portion thereof with a transitional graphical user interface, as shown and described. 